1. Field of the Invention
The present invention relates to the structure of an upper frame for supporting a cabin of construction machinery, and more particularly to a cabin supporting structure provided under a cabin in the form of a fixture, structure, cast member or sheet, whereby when a vertical load or rearward load is applied to the cabin, for example, due to a rollover accident of the construction machinery, and thus the cabin structure is plastically deformed, the cabin supporting structure disperses the vertical load or rearward load applied to the cabin structure.
2. Description of the Prior Art
FIG. 1 is a side view illustrating the construction of a conventional excavator.
Referring to FIG. 1, the conventional excavator includes a lower driving structure 2 having a traveling apparatus, and an upper swing structure 6 having an operation device 4, such as an arm or a bucket, and being swiveled around the lower driving structure 2 through a swing motor and a reduction device.
FIG. 2 is a perspective view illustrating the construction of an upper frame of a conventional excavator.
Referring to FIG. 2, an upper frame 18 is installed under the lower end of the upper swing structure 6 in a rectangular shape. The upper frame 18 includes a center frame 10 fitted with the operation device, a right frame 12 installed on the right side of the center frame 10 and fitted with an engine, a cooling device, diverse units associated with travel and operation of the excavator, and a left frame 16 installed on the left side of the center frame 10 and fitted with a cabin 14.
The center frame 10 has a bottom plate 20 fitted with a swing ring gear, and a lateral plate 22 installed perpendicular to the bottom plate 20 and coupled to the operation device. The left and right frames 16 and 12 have a longitudinally extended side channel 24 and a plurality of side frames 26 laterally extended to connect the center frame 10 to the side channel 24, respectively.
A plurality of vibration absorption devices (not shown) are installed on the side frame 26 of the left frame 16 corresponding to the lower portion of the cabin 10, thereby absorbing vibrations from the engine, the cooling device, and the travel and operation of the excavator, thus preventing the vibration from being transferred to the cabin 14.
FIG. 3 is a perspective view illustrating the construction of a conventional upper frame on which the cabin 14 is mounted.
Referring to FIG. 3, the cabin 14 includes a base plate (not shown) installed on the bottom surface thereof, a vertically extended front pillar 30, a vertically extended center pillar 32, and a vertically extended rear pillar 34 that are assembled on the front, middle, and rear portions of the base plate by fastening means, respectively. A door and a window are installed among the pillars 30, 32, and 34 by welding or bolting.
In order to protect an operator in the cabin 14 against the vertical load or rearward load and to minimize the plastic deformation of the cabin 14 when a rollover accident occurs during an excavation work on the spot, a reinforcing member may be provided in the pillars 30, 32, and 34.
Therefore, although the shock is applied to the cabin from the exterior, the load is preferentially dispersed by the pillars or the reinforcing member to protect the operator.
However, referring to FIG. 4 which is a perspective view illustrating the state in which the vertical load and the rearward load are applied to the cabin of FIG. 3, there is a problem that when the cabin 14 is plastically deformed by the vertical load or rearward load, the upper frame 18 cannot effectively support the vertical strength of the pillars 30, 32, and 34 or the reinforcing member, or cannot disperse the excessive vertical load or rearward load.
In the case in which the excessive load or the rearward load is applied to the conventional cabin structure, the load is dispersed by the pillar or reinforcing member of the cabin structure, but the dispersed load is not again dispersed by the upper frame.